Topic 11: Human Health and Physiology

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Topic 11 Human Health and Physiology

• 11.4 Reproduction

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11.4.1 Annotate a light micrograph of testis
tissue to show the location and function of
interstitial cells (Leydig cells) germinal
epithelial cells, developing spermatozoa and
Sertoli cells
http//www.indigo.com/software/gphpcd/his89-92.htm
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11.4.1 Annotate a light micrograph of testis
tissue to show the location and function of
interstitial cells (Leydig cells) germinal
epithelial cells, developing spermatozoa and
Sertoli cells
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11.4.2 Outline the process involved in
spermatogenesis within the testis, including
mitosis, cell growth, the two divisions of
meiosis and cell differentiation

• Spematogenesis the process of making sperm
• Mitosis ,meiosis I and meiosis II are involved
• Meiosis I is stimulated by FSH
• Meiosis II is stimulated by testosterone
• After meiosis I, there are two spermatocytes with
  homologous pairs of chromosomes
• After meiosis II, there are four haploid
  spermatids
• The last step, differentiation, converts the
  spermatocytes into mature spermatozoa
• This stage is stimulated by testosterone

http//wps.aw.com/bc_martini_eap_4/40/10469/268029
8.cw/content/index.html
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11.4.3 State the role of LH, testosterone, and
FSH in spermatogenesis

• There are three hormones that play a role in
  spermatogenesis
• Follicle stimulating hormone produced in the
  pituitary gland
• FSH stimulates sperm production in the
  seminiferous tubules and stimulates division and
  maturation of the Sertoli cells
• Lutenizing hormone produced in the pituitary
  gland
• LH Stimulates the interstitial cells (Leydig
  cells) to produce testosterone
• Testosterone produced in the Leydig cells of
  the testis
• Testosterone promotes spermiogenesis (the
  maturation of spermatids into spermatozoa)

billboardmama.com
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11.4.4 Annotate a diagram of the ovary to show
the location and function germinal epithelial,
primary follicles, mature follicle and secondary
oocyte

• Ovulation caught on film http//www.youtube.com/w
  atch?v2-VKgdhfNpY

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11.4.4 Annotate a diagram of the ovary to show
the location and function germinal epithelial,
primary follicles, mature follicle and secondary
oocyte
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11.4.5 Outline the process in oogenesis within
the ovary, including mitosis, cell growth, the
two divisions of meiosis, the unequal division of
the cytoplasm and the degeneration of the polar
body

• Oogenesis The production of a mature egg (ovum)
• begins in the ovaries of the female fetus before
  birth, but the final development of oocytes is
  completed in adult life
• Mitosis produces the germ cell which will later
  mature into a primary oocyte (2n)
• Meiosis I occurs creating a secondary oocyte and
  a polar body (haploid)
• The polar body is smaller than the oocyte
  (unequal division)

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11.4.5 Outline the process in oogenesis within
the ovary, including mitosis, cell growth, the
two divisions of meiosis, the unequal division of
the cytoplasm and the degeneration of the polar
body

• Meiosis II then occurs resulting in three polar
  bodies and an ootid
• Meiosis II does not occur until after
  fertilization
• The three polar bodies are smaller than the ootid
  (unequal division)
• Ootid later differentiates into an ovum and the
  polar bodies degenerate

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11.4.6 Draw and label a diagram of a mature sperm
and egg
inquisitr.com
fainaboxvifici.blogspot.com
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11.4.6 Draw and label a diagram of a mature sperm
and egg
The great sperm race http//www.youtube.com/watch?
vgAnMymnJiLM
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11.4.6 Draw and label a diagram of a mature sperm
and egg
ouhsc.edu
click4biology.info
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11.4.6 Draw and label a diagram of a mature sperm
and egg
http//sciencevideos.wordpress.com/ahl/11-human-ph
ysiology-ahl/reproduction-ahl/
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11.4.7 Outline the role of the epididymis,
seminal vesicles, and prostate gland in the
production of semen

• Semen consists of
• Sperm
• Fluid from the prostate
• Fluid from the seminal vessicles
• Sperm cells are produced in the seminiferous
  tubules and later pass to the very-coiled
  epididymis where maturation is completed (this is
  where the sperm become mobile)
• Sperm are transported from the male to the female
  in a nutritive fluid (semen) secreted by the
  prostate glands and glands in the seminiferous
  tubules. The semen provides the sperm with
  fructose (high energy)
• The semen is also slightly alkaline which will
  neutralize the acidic environment of the vagina
• Seminal vesicles add nutrients that include
  fructose sugar for respiration
• Also adds mucus to protect sperm in the cell

The Great Sperm Race Part II http//www.youtube.c
om/watch?vCNOLEQwKlF4featurerelated
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11.4.8 Compare the process of spermatogenesis and
oogenesis, including the number of gametes and
the timing of the formation and release of gametes
One gamete is formed per germ cell (plus polar
bodies)
Four gametes are formed per each germ cell
Gamete is released once a month
Form continuously
Gametes can be released any time
Spermatogenesis
Oogenesis
Formed in the embryo before birth
All develop into mature gamete
Meiosis I is completed but meiosis II only goes
until prophase II and then finishes fertilization
Formed from the time of puberty throughout life
Form once a month
Meiosis I and II go to completion during
spermatogenesis
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11.4.8 Compare the process of spermatogenesis and
oogenesis, including the number of gametes and
the timing of the formation and release of gametes
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11.4.9 Describe the process of fertilization,
including the acrosome reaction, penetration of
the egg membrane by a sperm and the cortical
reaction

• Fertilization is the fusion of male and female
  gametes
• Occurs internally in mammals in the upper part of
  the oviduct

Step 1 The sperm passes between the cells of the
follicle Step 2 When the sperm reaches the
jelly coat the head releases hydrolitic enzymes
(acrosome reaction) Step 3 Sperm and egg
bind .
See animation at http//bcs.whfreeman.com/thelife
wire/content/chp43/4301s.swf
http//www.bio.davidson.edu/Courses/Molbio/MolStud
ents/spring2005/Champaloux/fertilization.jpg
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11.4.9 Describe the process of fertilization,
including the acrosome reaction, penetration of
the egg membrane by a sperm and the cortical
reaction

• Steps 4 and 5 The sperm reaches the plasma
  membrane of the secondary oocyte and the head of
  the sperm is engulfed by the plasma membrane of
  the secondary oocyte
• Step 6 Cortical granules are exocytosed by the
  oocyte and create a barrier to disallow the entry
  of another sperm (called the cortical reaction)
• These series of events stimulates the completion
  of meiosis II in the nucleus of the secondary
  oocyte
• Step 7 The haploid male nucleus and haploid
  female nucleus come together to form the diploid
  nucleus of the zygote
• .

http//www.bio.davidson.edu/Courses/Molbio/MolStud
ents/spring2005/Champaloux/fertilization.jpg
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11.4.9 Describe the process of fertilization,
including the acrosome reaction, penetration of
the egg membrane by a sperm and the cortical
reaction

• Plat the Great Sperm Race Game at
• http//www.channel4.com/programmes/the-great-sperm
  -race/articles/the-great-sperm-race-game

Great Sperm Race Part III http//www.youtube.com
/watch?vndrBCeqOqW0featurerelated Great
Sperm Race Part IV http//www.youtube.com/watch?v
kvAm99AGbrAfeaturerelated Great Sperm Race
Part V http//www.youtube.com/watch?vVlSLt_uMExk
featurerelated
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11.4.10 Outline the role of HCG in early pregnancy

• The outer cells of the newly formed blastocyst
  secrete human chorionic gonadotrophin (HCG).

This hormone keeps the corpus luteum alive so
it will continue to produce progesterone, which
in turn maintains the endometrium Eventually,
the placenta will produce progetserone and the
corpus luteum is no longer needed Also,
progesterone inhibits the production of LH and
FSH. This will inhibit ovulation .
ehd.org
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11.4.11 Outline the early embryo development up
to the implantation of the blastocyst

• Fertilization occurs in the upper oviduct and the
  zygote is transferred down the oviduct by ciliary
  action
• Mitosis and cell division begin in a process
  called cleavage. Develops into a morula
• When the embryo reaches the uterus it is a mass
  of tiny cells called blastomeres
• Further division occurs and the blastomeres
  arrange themselves and form a blastocyst
• At about seven days after fertilization the
  blastocyst (consisting of about 100 cells)
  implants itself onto the endometrium
• The blastocyst will grow trophoblastic villi
  which absorb nutrients from the endometrium
  (before the placenta has developed)

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11.4.12 Explain how the structure and functions
of the placenta, including its hormonal role in
its secretion of estrogen and progesterone,
maintain pregnancy
siumed.edu
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11.4.12 Explain how the structure and functions
of the placenta, including its hormonal role in
its secretion of estrogen and progesterone,
maintain pregnancy

• The function of the placenta is to exchange
  material between the mothers blood and the
  fetus blood, but it is also an endocrine gland
• Early in pregnancy, progesterone is produced by
  the corpus luteum
• This role is later taken over by the placenta
• Progesterone
• reduces contractions to maintain pregnancy
• reduces the effectiveness of the mother's immune
  system to prevent the production of antibodies
  against the baby
• When progesterone levels drop lactation begins
• Estrogen
• results in an increase in size of the
  muscles of the uterus
• stimulates the development of the
  mammary glands

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11.4.14 State that materials are exchanged
between the maternal and fetal blood in the
placenta

• It is a disc shaped structure composed of both
  maternal endometrial tissue and fetal membrane
  tissue

At this location, the maternal and fetal blood
are brought very close to each other over a large
surface area but they do not mix The exchange
that occurs across the placenta is by both
diffusion and active transport
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11.4.14 State that materials are exchanged
between the maternal and fetal blood in the
placenta

• The following exchanges occur
• respiratory gases O2 diffuses across the
  membrane from maternal hemoglobin to fetal
  hemoglobin and CO2 diffuses in the opposite
  direction
• water by osmosis
• glucose facilitated diffusion
• amino acids and ions active transport
• excretory waste products urea
• antibodies freely cross the membrane for
  protection (passive immunity)
• The placenta is a barrier to bacteria

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11.4.13 State that the fetus is supported and
protected by the amniotic sac and amniotic fluid

• The fetus is wrapped in a sac (amniotic sac)
  which is filled with fluid (amniotic fluid)
• This protects the baby from mechanical harm
• Also protects the fetus from infections

dna-laboratories.com
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11.4.15 Outline the process of birth and its
hormonal control, including the changes in
progesterone and oxytocin levels and positive
feedback

• At about week 38, progesterone levels drop and
  contractions of the uterus begin
• The babies head pushes against the cervix
• This causes stretching of the cervix and
  stimulates stretch sensitive nerve receptors
• These receptors send a signal to the brain which
  results in the release of oxytocin from the
  posterior lobe of the pituitary gland
• Oxytocin relaxes the fibers that hold the pelvis
  together and also causes stronger and more
  powerful contractions
• The cervix stretches even further sending more
  signals to brain, thus releasing more oxytocin
  (positive feedback loop)
• Eventually the baby is born, the cervix is not
  stretched anymore and the loop is turned off